Jim, why don't you do instead of preaching? Offer to prepare HTML for post-processors that don't like preparing HTML, but can give you files marked with a reasonable extension of DP markup of your choice.
It would be much more beneficial to PG if I, and others, were allowed to choose which books we see as most needing of having their formatting fixed, rather than having Carlo dictate to us which books to fix. This is consistent with PG philosophy that volunteers work on the books they think are important, rather than being told what books to work on. I would be happy if Greg, or others at PG made suggestions of which books most need their formatting fixed based on frequency of download. This is certainly easy to accomplish. Certainly Michael Hart used to make suggestions about what books are worth doing, and I was happy to do a number of books at his suggestion -- because I found when I explored the issue that he did have good taste in books -- the books he suggested were historically significant, were good reads, and were books that could be done in a reasonable amount of time and effort, including HTML formatting. I personally am not interested in fixing the formatting on the next yet-another DP "Tom and Sally ride their Pony to the Moon." Nor am I interested in tackling someone's Italian Mathematical Treatise. If trying to use epubmaker to reverse every act of foolishness is a fool's errand, then doubly so to think that I or anyone can fix every act of foolishness by hand -- if PG is not willing to tackle the problem of vetting the continuing new HTML being submitted in the first place. PG could just implement their implied threat as a test, namely have the WW (temporarily) yank the CSS, and then see if a submission still made the remotest sense. I think that answer should be obvious.